A prior U.S. Pat. No. 4,093,117 and dated June 6, 1978, was granted to me and discloses and claims a one piece mailer made from relatively stiff cardboard material, with a slide having a slide card movable therealong to form a slide rule and information designating device.
In this envelope, the slide forms one side of the envelope and a mailing flap forms the opposite side of the envelope. Such an envelope has been an attractive item particularly for sales literature but can contain nothing other than letters, sales literature or flat articles and is not suitable for packaged goods and, therefore, in effect is principally an envelope and information designating device on one side of the envelope.